“Luster” refers to an optical property of materials exhibiting a sort of glow from reflected light. “Metallic luster” is generally considered an inherent characteristic of metals, so much so that materials exhibiting this type of gloss or sheen are often merely referred to as looking “metallic.” As expanded colors and appearances are sought for home and office decorative printing, inks producing metallic luster are noticeably limited among available options. Gold ink containing pure gold nanoparticles has been reported for printed electronics applications. However, such ink generally is cost prohibitive and ineffective for home and office use. Silver ink containing pure silver nanoparticles (i.e., silver metal ink) carries environmental concerns, requiring “Dangerous to the Environment” labeling at least in European Union countries. Additionally, known silver metal ink has exhibited poor smudge resistance and oxidative fading.